1. Technical Field
The present invention relates to a polarizing plate and a liquid crystal display apparatus including the same.
2. Description of the Related Art
Polarizing plates are used to control the oscillation direction of light in order to visualize the display patterns of a liquid crystal display apparatus inside and outside a liquid crystal cell. Although liquid crystal display apparatuses were initially applied to small apparatuses, recently, liquid crystal display apparatuses are used in a wide variety of applications, including notebook computers, liquid crystal monitors, liquid crystal color projectors, liquid crystal televisions, navigation systems for vehicles, personal phones, measurement instruments for use indoors and outdoors, and the like. Liquid crystal monitors and liquid crystal televisions generally employ a high-brightness backlight unit. Thus, a polarizing film of a polarizing plate is typically used to exhibit better performance.
The polarizing plate typically includes a polarizer, a protective film on one side of the polarizer, and a retardation film for imparting a phase difference on the other side of the polarizer. In the polarizing plate, when the polarizer and the retardation film are laminated, axis distortion between the absorption axis of the polarizer and the fast axis of the retardation film should be prevented in order to maximize polarization efficiency and allow the liquid crystal display apparatus to exhibit maximized contrast ratio. However, when the protective film and the retardation film have an ultrahigh phase difference, the polarizing plate can exhibit reduced polarization efficiency, and thus the liquid crystal display apparatus can exhibit deteriorated contrast ratio.
Polarization efficiency and contrast ratio are important factors in the evaluation of a liquid crystal display panel. Although modifications in the process conditions (such as elongation, the material for the polarizing plate, and the like) have been attempted to improve these characteristics, only limited benefits have been realized.